This invention relates generally to pumps of the type used in semiconductor manufacturing operations for dispensing photochemical and other such liquids, and more particularly, to methods and apparatus for interfacing such pumps with track equipment used for wafer handling in such semiconductor processing.
In the manufacture of semiconductor components such as integrated circuits, semiconductor wafers, as of silicon, are subjected to a series of processing operations involving depositing layers of coatings on the wafers, patterning the coatings, etching the coatings to remove material, etc. Each of these processing operations is performed at a different processing station. The wafers are moved between stations and the processing apparatus at each station is controlled by a machine known as a track. The track not only moves wafers between stations, but also controls pumps which dispense photochemicals onto the wafers and controls the start, the stop, and the timing of pumping operations. This requires communications between the pump and the track, which requires that the pump be interfaced to the track. This has traditionally been problematic. Track interfaces involve electrical interfaces, timing interfaces, and hardware interfaces of the inputs and outputs according to the track type and to the pump. There is no standard or universal track interface. Different track manufacturers employ different interfaces, and even different tracks produced by the same manufacturer have different interfaces. Furthermore, the increased sophistication and complexity of tracks necessitate a corresponding increase in sophistication and complexity of the interface. There is also no standard or universal pump interface. Different pumps also have different interfaces.
In the past, a pump-to-track interface setup has been limited by the state and hardware requirements of the interface. Normally, interfacing pumps to tracks required switches and jumpers, and in many cases custom hardware in order to match the unique timing and electrical characteristics of different and perhaps incompatible pumps and tracks. The timing of the signals which are output to the track from a pump may be fixed with respect to a particular pump and depend upon the characteristics and timing of the pump cycle. The signals may or may not be compatible with the track interface, frequently necessitating custom hardware and interfaces.
The multiplicity of different interfaces between different tracks and different pumps has posed problems for process engineers attempting to interface different pumps and tracks, and has inhibited the ability to easily change system hardware. With cleanroom space at a premium and increased demand for semiconductors, the demands on track performance have increased. This has caused track manufacturers to allocate less space for pumps which makes changing of jumpers or switches, or adding of different interface hardware difficult.
It is desirable to provide a way of quickly and easily accommodating the various interface requirements of different tracks and different pumps in a single, easily adapted pump interface without the necessity of extensive hardware changes or custom setups, and it is to these ends that the present invention is directed.
The invention affords a universal track interface which enables track types comprising the input, output, electrical, hardware, timing, etc. requirements necessary to accommodate different tracks and different pumps to be pre-selected and stored so that a type to accommodate a particular pump and track can be automatically selected and instantiated without the necessity of manually reconfiguring the interface with switches, jumpers or additional hardware to accommodate different interface requirements. The various types may be stored in memory, such as firmware, in the pump, and selected using an appropriate designator, such as a number, to interface the pump to a particular track. Additionally, the track interface may allow a user to customize and store a user-created custom track interface for a particular configuration, either to interface a pump to a track or to change the interface to vary the timing, for example, and other characteristics in order to customize the track interface.
In one aspect, the invention affords an apparatus for interfacing a pump and a track in a semiconductor manufacturing process which includes a memory for storing a plurality of track types which comprise parameters which define the interface requirements for a predetermined track. A control means responsive to the selection of a track type automatically configures the interface hardware in accordance with the parameters of the selected track type in order to interface the track and the pump.
More specifically, the interface comprises optical couplers for electrically isolating control signals between the pump and the track. The interface further includes electrical circuits associated with the pump side of the interface and the track side of the interface, the electrical circuits automatically configuring the interface as a sink for receiving current from the track or as a source for supplying current to the track in accordance with the track type. Additionally, the control signals also select the active state of the control signals between the track and the pump as being either high or low in accordance with track type.
In another aspect, the invention affords apparatus for interfacing a device to a track in a semiconductor manufacturing process, in which the device and the track have a plurality of input and output lines. An electrical circuit having a first portion for the track and a second portion for the device are responsive to configuration signals which define the track interface for configuring the interface according to the track type. The configuration signals enable the interface to be configured as a sink for receiving current from the track or as a source for supplying current to the track in accordance with track type, and select the active state of the control signals as being high or low in accordance with track type.